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# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
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# http://www.apache.org/licenses/LICENSE-2.0
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# See the License for the specific language governing permissions and
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import asyncio
import json
import threading
from typing import List

import pytest

from dynamo.llm import ApproxKvIndexer, KvEventPublisher, KvIndexer, RadixTree
from dynamo.runtime import Component, DistributedRuntime

pytestmark = pytest.mark.pre_merge


@pytest.fixture
async def distributed_runtime():
    """Function-scoped runtime fixture for distributed runtime tests."""
    loop = asyncio.get_running_loop()
    runtime = DistributedRuntime(loop, "etcd", "nats")
    yield runtime
    runtime.shutdown()


@pytest.mark.timeout(5)  # Expected: ~1s, timeout set to 5x for safety
def test_radix_tree_binding():
    """Test RadixTree binding directly with store event and find matches"""
    import json

    # Create RadixTree instance
    radix_tree = RadixTree()

    # Create a store event with parent_hash=None, block_hash=0
    # Following the KvCacheEvent format from the Rust protocols
    store_event = {
        "event_id": 1,
        "data": {
            "stored": {
                "parent_hash": None,
                "blocks": [
                    {
                        "block_hash": 0,
                        "tokens_hash": 0,  # Using 0 for both hashes to match tokens [0]
                    }
                ],
            }
        },
    }

    # Convert to JSON bytes
    event_bytes = json.dumps(store_event).encode("utf-8")

    # Apply the event to worker_id 0
    worker_id = 0
    radix_tree.apply_event(worker_id, event_bytes)

    # Find matches for tokens [0]
    # The sequence parameter expects token hashes, so we use [0] to match tokens_hash=0
    overlap_scores = radix_tree.find_matches([0])

    # Verify the results
    # Note: scores is now Dict[(worker_id, dp_rank), score]
    assert overlap_scores.scores is not None
    assert (
        len(overlap_scores.scores) == 1
    ), f"Expected 1 worker in scores, got {len(overlap_scores.scores)}"
    worker_key = (worker_id, 0)  # (worker_id, dp_rank)
    assert (
        worker_key in overlap_scores.scores
    ), f"Worker {worker_key} not found in scores"
    assert (
        overlap_scores.scores[worker_key] == 1
    ), f"Expected score 1 for worker {worker_key}, got {overlap_scores.scores[worker_key]}"

    blocks = radix_tree.dump_tree_as_events()
    assert len(blocks) == 1, f"Expected 1 block event, got {len(blocks)}"
    json.loads(blocks[0])  # check valid json

    # cleanup
    radix_tree.remove_worker(worker_id)
    blocks_empty = radix_tree.dump_tree_as_events()
    assert (
        len(blocks_empty) == 0
    ), f"Expected 0 block events after removal, got {len(blocks_empty)}"

    print(
        f"✓ RadixTree test passed: worker {worker_key} has score {overlap_scores.scores[worker_key]}"
    )


@pytest.mark.timeout(5)  # Expected: ~1s, timeout set to 5x for safety
@pytest.mark.parametrize("num_threads", [2, 3, 5, 128])
@pytest.mark.parametrize("prepopulate_worker_ids", [True, False])
@pytest.mark.parametrize("expiration_duration_secs", [None])
@pytest.mark.parametrize("is_threaded", [True, False])
def test_radix_tree_thread_safety(
    num_threads,
    prepopulate_worker_ids,
    expiration_duration_secs,
    is_threaded,
):
    """Test RadixTree thread safety by applying events from multiple threads."""
    radix_tree = RadixTree(expiration_duration_secs=expiration_duration_secs)
    threads = []
    done_counter = 0
    exception_counter = 0

    def worker(worker_id, prepopulate_worker_ids: bool = False):
        try:
            nonlocal done_counter
            worker_id = worker_id
            hash = worker_id
            if prepopulate_worker_ids:
                hash = (
                    2**32 - worker_id
                )  # use different hash for prepopulate_worker_ids
            assert 0 <= hash < 2**64  # needs to be valid u64
            store_event = {
                "event_id": worker_id,
                "data": {
                    "stored": {
                        "parent_hash": None,
                        "blocks": [
                            {
                                "block_hash": hash,
                                "tokens_hash": hash,
                            }
                        ],
                    }
                },
            }
            event_bytes = json.dumps(store_event).encode("utf-8")
            radix_tree.apply_event(worker_id, event_bytes)
            if not prepopulate_worker_ids:
                done_counter += 1
        except Exception as e:
            print(f"Exception in worker {worker_id}: {e}")
            nonlocal exception_counter
            exception_counter += 1

    if prepopulate_worker_ids:
        for i in range(num_threads):
            worker(i, prepopulate_worker_ids=True)
        assert (
            exception_counter == 0
        ), f"Warmup: expected 0 exceptions, got {exception_counter}"

    for i in range(num_threads):
        if is_threaded:
            t = threading.Thread(target=worker, args=(i,))
            threads.append(t)
            t.start()
        else:
            worker(i)
    if is_threaded:
        timeout = 10  # seconds
        for t in threads:
            t.join(timeout)
            assert not t.is_alive(), "Thread timed out"
    assert exception_counter == 0, f"Expected 0 exceptions, got {exception_counter}"
    assert (
        done_counter == num_threads
    ), f"Expected {num_threads} done, got {done_counter}"

    for i in range(num_threads):
        overlap_scores = radix_tree.find_matches([i])
        assert overlap_scores.scores is not None
        worker_key = (i, 0)
        assert (
            worker_key in overlap_scores.scores
        ), f"Worker {worker_key} not found in scores"
        assert (
            overlap_scores.scores[worker_key] == 1
        ), f"Expected score 1 for worker {worker_key}, got {overlap_scores.scores[worker_key]}"
    # get all blocks
    blocks = radix_tree.dump_tree_as_events()
    expected_blocks = num_threads + (prepopulate_worker_ids * num_threads)
    assert (
        len(blocks) == expected_blocks
    ), f"Expected {expected_blocks} block events, got {len(blocks)}"
    # remove single worker
    radix_tree.remove_worker(0)
    expected_blocks_after_removal = expected_blocks - (
        2 if prepopulate_worker_ids else 1
    )
    blocks_after_removal = radix_tree.dump_tree_as_events()
    assert (
        len(blocks_after_removal) == expected_blocks_after_removal
    ), f"Expected {expected_blocks_after_removal} block events after removal, got {len(blocks_after_removal)}"


@pytest.mark.asyncio
@pytest.mark.timeout(5)  # Expected: ~1s, timeout set to 5x for safety
async def test_event_handler(distributed_runtime):
    kv_block_size = 32
    namespace = "kv_test"
    component = "event"
    kv_listener = distributed_runtime.namespace(namespace).component(component)

    # publisher
    # Get actual worker_id from component (KvEventPublisher ignores the passed worker_id and uses component's connection_id)
    # Create a dummy endpoint to access connection_id since Component doesn't expose it directly
    dummy_endpoint = kv_listener.endpoint("dummy")
    worker_id = dummy_endpoint.connection_id()
    event_publisher = EventPublisher(kv_listener, worker_id, kv_block_size)

    # indexer
    indexer = KvIndexer(kv_listener, kv_block_size)

    test_token = [3] * kv_block_size
    lora_id = 0  # lora_id is not used in the indexer
    scores = await indexer.find_matches_for_request(test_token, lora_id)
    assert not scores.scores

    event_publisher.store_event(test_token, lora_id)
    # Wait for the event to be processed (sent asynchronously)
    await asyncio.sleep(0.2)

    scores = await indexer.find_matches_for_request(test_token, lora_id)
    worker_key = (worker_id, 0)  # (worker_id, dp_rank)
    assert scores.scores, "No scores found"
    assert worker_key in scores.scores, f"Worker {worker_key} not found in scores"
    assert (
        scores.scores[worker_key] == 1
    ), f"Expected score 1, got {scores.scores[worker_key]}"

    # Remove event and verify
    event_publisher.remove_event()
    await asyncio.sleep(0.2)

    scores = await indexer.find_matches_for_request(test_token, lora_id)
    assert not scores.scores, f"Scores still present: {scores.scores}"


@pytest.mark.asyncio
@pytest.mark.timeout(5)  # Expected: ~1s, timeout set to 5x for safety
async def test_approx_kv_indexer(distributed_runtime):
    """Test ApproxKvIndexer with TTL-based block tracking"""
    kv_block_size = 32
    namespace = "kv_test"
    component = "approx_kv"
    kv_listener = distributed_runtime.namespace(namespace).component(component)

    # Create ApproxKvIndexer with default TTL (120s)
    indexer = ApproxKvIndexer(kv_listener, kv_block_size)

    tokens = [0] * (kv_block_size * 2)

    # Initially no matches
    scores = await indexer.find_matches_for_request(tokens)
    assert not scores.scores

    worker_id = 0

    # Process routing decision - this should add blocks to the indexer
    await indexer.process_routing_decision_for_request(tokens, worker_id)

    # Now we should have matches
    scores = await indexer.find_matches_for_request(tokens)
    assert scores.scores
    worker_key = (worker_id, 0)  # (worker_id, dp_rank)
    assert worker_key in scores.scores
    assert scores.scores[worker_key] == 2  # 2 blocks (tokens is 2 blocks long)


class EventPublisher:
    def __init__(self, component: Component, worker_id: int, kv_block_size: int):
        self.publisher = KvEventPublisher(component, worker_id, kv_block_size)
        # Counter for generating unique block hashes (event_id is now managed internally by publisher)
        self.block_hash_counter = 0
        self.block_hashes: List[int] = []

    def store_event(self, tokens, lora_id):
        # Parent hash should reference the last published block, not the current one
        parent_hash = self.block_hashes[-1] if self.block_hashes else None
        self.publisher.publish_stored(
            tokens,  # token_ids
            [
                len(tokens),
            ],  # num_block_tokens
            [
                self.block_hash_counter,
            ],  # block_hashes
            lora_id,  # lora_id
            parent_hash,  # parent_hash
        )
        self.block_hashes.append(self.block_hash_counter)
        self.block_hash_counter += 1

    def remove_event(self):
        self.publisher.publish_removed(
            [
                self.block_hashes[-1],
            ],  # block_hashes
        )
